I. Field of the Invention
The present invention relates to a mechanical part having ceramic and metal sections soldered together. The present invention further relates to a method of producing such a ceramic-metal composite mechanical part.
II. Description of the Prior Art
Ceramics have excellent heat and wear resisting properties and have recently been used in many cases in the form of ceramic-metal composite bodies in which a ceramic section is soldered to a metal section, due to its mechanical characteristics. For example, a rocker arm for an internal combustion engine has at its valve contacting portion a ceramic tip which is soldered to a metal main body. Prior to the soldering, the joining surface of the ceramic tip to be joined with the metal main body is metallized for example by vacuum evaporation.
The ceramic tip is metallized only at the joining surface. Thus, when an excess amount of solder is used for the purpose of removing the pores and foreign matter from the joint between the ceramic tip and metal main body, run solder is caused on the side surface of the main body as well as an irregular thickness of the solder layer and therefore an inclination of the ceramic tip. Since it is necessary to attain a certain degree of parallelization or straightness of the ceramic tip relative to the reference surface of the metal main body, the sliding surface of the ceramic tip needs to be ground to size with respect to the reference surface after the ceramic tip is soldered to the metal main body. Furthermore it is necessary to carry out a machining for removing the run solder, thus resulting in increased manufacturing cost. Further, if the amount of solder is reduced as small as possible, the pores and foreign matters cannot be removed sufficiently, thus resulting in considerably reduced strength of the soldered joint between the ceramic tip and metal main body.